While transfer and injection molded, fiber reinforced resin parts have been produced commercially for some time, for use in a variety of industries including the aircraft industry, and provide considerable structural strength, there is a need for even stronger fastener products, such as bolts with axially elongate shanks, which may be subjected to unusually high stresses. Parts produced commercially heretofore, have incorporated chopped glass, carbon, and aramid fibers, optimally on the order of 1/4 to 1 inch in length (but dependent on the nature of the part possibly from 0.010 to three inches in length), randomly dispersed in thermosetting resins such as epoxy and vinyl ester compounds, and thermoplastic resins including polymeric amides, i.e., "nylon". In such parts, the relatively short fibers (relative to the length of the part), do not, in any substantial number, assume an axial orientation in the finished product. To the best of my knowledge, there is no practical way to control the orientation of fibers in a transfer or injection molded part, where the material with entrained fibers is flowed into the mold cavity under very high pressures.
The present invention achieves the positive axial orientation of an elongate fiber bundle during the transfer molding process, and effectively bonds the fiber lengths with the resin making up the body of the product.
One of the prime objects of the present invention is to obtain a composite bolt having far greater strength in tension on the order, for example, of 3:1.
Still another object of the invention is to provide a bolt which has significantly higher strength in torsion, and in shear.
Still another object of the invention is to provide a process wherein the product is more reliably constructed, and the proportion of parts produced to standards is significantly improved.
Other objects and advantages of the invention will become apparent from the drawings I have included, and the description to follow.